Industrial chemicals · Taylor, TXTechnical Data Sheet
Sodium Hydroxide 50% Membrane Grade (Caustic Soda, Lye)
Membrane Grade · 50%
Identity & Composition
- Product Name
- Sodium Hydroxide 50% Membrane Grade (Caustic Soda, Lye)
- Alliance Code
- sodium-hydroxide-50-membrane-grade-caustic-soda-lye
- Grade
- Membrane Grade
- Concentration
- 50%
- CAS Number
- 1310-73-2PubChem
- Formula
- HNaOPubChem
- Molecular Weight
- 39.997PubChem
- Product Type
- solution
Specifications
| Test | Specification | Typical | Method | Source |
|---|---|---|---|---|
| Assay, sodium hydroxide (NaOH) | 49.5 – 51.5 WT. % | 50.0 WT. % | Titrimetry | Supplier specification |
| Sodium Chloride (NaCl) | 100 PPM max. | 25 PPM | Turbidimetry | Supplier specification |
| Iron (Fe) | 3 PPM max. | 0.5 PPM | Colormitry | Supplier specification |
| Sodium Carbonate (Na2CO3) | 0.1 WT. % max. | 0.03 WT. % | Titrimetry | Supplier specification |
| Sodium chlorate (NaClO3) | 40 PPM | 12 PPM | Ion Chromatography | Supplier specification |
| Sodium hydroxide (NaOH) | 49.5 – 51.5 WT. % | 50.0 WT. % | Titrimetry | Supplier specification |
| Sodium oxide (Na2O) | 38.3 – 40.0 WT. % | 39.15 WT. % | Calculated | Supplier specification |
| Sodium sulfate (Na2SO4) | 40 PPM | 5 PPM | Ion Chromatography | Supplier specification |
| Nickel (Ni) | 1.0 PPM Max | 0.2 PPM | ICP-OES | Interpreted |
| Mercury (Hg) | 0.05 PPM Max | 0.001 PPM | Cold vapor AAS | Interpreted |
| total alkalinity | 38.35 - 39.9 % | 38.74 % | — | Supplier specification |
| excess sodium hydroxide | 49.5 - 51 wt.% | 50.0 wt.% | — | Supplier specification |
| na2o | 37.97 - 39.9 % | 38.935 % | — | Supplier specification |
Specification values are guaranteed limits. Typical values are representative of production lots and are not guaranteed. Lot-specific certificates of analysis ship with every order.
Available GradesSame CAS, alternate grades and concentrations
| Grade | Concentration | Typical Assay | SKU | TDS |
|---|---|---|---|---|
| This grade Membrane Grade | 50% | — | current | current |
| ACS Grade | 50% | — | sodium-hydroxide-50-solution-acs-grade | View TDS → |
| ACS | 30% | — | sodium-hydroxide-30-acs-grade | View TDS → |
| Technical | 30% | — | sodium-hydroxide-30-technical-grade | View TDS → |
| — | 25% | — | sodium-hydroxide-25 | View TDS → |
| ACS Grade | 25% | — | sodium-hydroxide-25-acs-grade | View TDS → |
| ACS | 20% | — | sodium-hydroxide-20-acs-grade | View TDS → |
| Technical | 20% | — | sodium-hydroxide-20-technical-grade | View TDS → |
| ACS | 15% | — | sodium-hydroxide-15-acs-grade | View TDS → |
| Technical | 15% | — | sodium-hydroxide-15-technical-grade | View TDS → |
| ACS | 10% | — | sodium-hydroxide-10-acs-grade | View TDS → |
| Technical | 10% | — | sodium-hydroxide-10-technical-grade | View TDS → |
| ACS | 5% | — | sodium-hydroxide-5-acs-grade | View TDS → |
Typical assay shown is the rolling-window mean from the sibling product's most recent lots. Grade selection drives downstream end-use — verify the sibling grade matches your specification before substitution.
Physical & Chemical Properties
One or more physical-property values are temporarily suppressed pending verification against vendor COA data. For complete properties refer to the Safety Data Sheet (SDS) or contact sales@alliancechemical.com.
| Property | Value | Source |
|---|---|---|
| Form | Liquid solution | Published reference |
| Color | Max 20 | Interpreted |
| Odor | ... Odorless ... | Published reference |
| Specific Gravity (20 °C) | 1.520 - 1.540 | Interpreted |
| Density | 1.53 (50% w/w aqueous solution, 20 °C) | Published reference |
| Boiling Point | Not characterized for the 50% solution | Published reference |
| Melting Point | Not characterized for the 50% solution | Published reference |
| Flash Point | N/A | Published reference |
| Vapor Pressure | 0 mmHg (approx) (NIOSH, 2024) | Published reference |
Strong base — hygroscopic; values may drift in opened containers. See storage guidance.
Materials of Construction
| Material | Rating | Conditions | Source |
|---|---|---|---|
| HDPE / polyethylene (bottle, drum) | Compatible | 50-52% (w/w) sodium hydroxide solution as packaged for sale by the supplier; no temperature stated | media.vwr.com |
Compatibility is drawn from published manufacturer and supplier documentation for this product; each rating is sourced. Confirm against your specific duty cycle before equipment selection.
Materials Selection Tool
Showing 14 of 14 materials compatible at the selected envelope.
| Material | Rating | Max T (°C) | Notes |
|---|---|---|---|
Buna-N (NBR) elastomer | Fair | 40 | Limited service life |
EPDM elastomer | Excellent | 100 | Standard for caustic gaskets. |
Viton (FKM) elastomer | Poor | — | Hydrolyzes in caustic; do not use. |
PTFE fluoropolymer | Excellent | 200 | Universal compatibility. |
304 stainless steel metal | Good | 80 | Acceptable for dilute caustic |
316L Stainless Steel metal | Excellent | 80 | Preferred metal for caustic service. |
Aluminium metal | Not recommended | — | Rapid attack; generates hydrogen |
Carbon Steel metal | Good | 60 | Acceptable below 70 °C; caustic embrittlement risk above. |
Nickel metal | Excellent | 100 | Preferred for high-temperature caustic |
Zinc / galvanized steel metal | Not recommended | — | Rapid corrosion |
HDPE thermoplastic | Excellent | 60 | Standard tote/drum material. |
Polypropylene thermoplastic | Excellent | 80 | Excellent caustic service to 50 %. |
PP thermoplastic | Excellent | 80 | Preferred for elevated temperature |
PVC thermoplastic | Good | 40 | Acceptable for ambient service |
Regulatory & Transport
DOT / 49 CFR
- UN Number
- UN1824Adjudicated
- Hazard Class
- 8Adjudicated
- Packing Group
- IIAdjudicated
- Proper Shipping Name
- Sodium hydroxide solutionAdjudicated
GHS / OSHA HazCom 2012
- Signal Word
- DangerAdjudicated
- H-Codes (Hazard Statements)
- H290, H314ECHA CLP Annex VI
- P-Codes (Precautionary Statements)
- P234, P260, P264, P280, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P363, P405, P501ECHA CLP Annex VI
Occupational Exposure Limits
- OSHA PEL (29 CFR 1910.1000)
- 2 mg/m³ TWAOSHA 29 CFR 1910.1000
- ACGIH TLV
- —no canonical
- NIOSH REL
- 2 mg/m³ ceilingNIOSH Pocket Guide
- NIOSH IDLH
- 10 mg/m³NIOSH Pocket Guide
Transport descriptions reflect 49 CFR 172.101 lookup at time of publication. Sourced data: ECHA CLP Annex VI for harmonised classifications, NIOSH Pocket Guide for REL/IDLH, OSHA Z-Tables for PEL. Always verify against the latest regulatory text before shipment-critical decisions.
Supplier Qualification Packet
One zipped download containing the TDS, SDS, latest lot COA (when available), and a fresh Letter of Continuing Guaranty for Sodium Hydroxide 50% Membrane Grade (Caustic Soda, Lye). Every file included is SHA-256 hashed and listed in a manifest your QA team can audit.
Catalog EquivalentsCross-reference vs major chemical suppliers
Sigma-Aldrich
| SKU | Grade | Conc. | Match | Notes |
|---|---|---|---|---|
| S5881 | ACS Reagent | ≥97% | Exact | Reagent grade, anhydrous pellets |
Cross-references are informational. Confirm against the manufacturer's current specification before substitution. Competitor trademarks are property of their respective owners.
Applications
- pH adjustment in water treatment; pulp and paper; textile scouring and dyeing; soap and detergent manufacturing; petroleum refining and oil drilling; aluminum processing; chemical synthesisbasekim.com
Applications are drawn from published manufacturer and supplier documentation; each is sourced. Suitability for a specific use is the buyer's to confirm.
Storage & Handling
- Recommended Storage
- Cool, dry, well-ventilated area in compatible containers (HDPE, lined steel — not aluminium). Tightly sealed; protect from atmospheric moisture and CO2. Segregate from acids and oxidizers.Class-level guidance — not product-specific; the SDS controls.
- Handling Precautions
- Use full PPE including chemical splash goggles and alkali-resistant gloves. Add base to water slowly with stirring. Highly exothermic dilution.Class-level guidance — not product-specific; the SDS controls.
- Incompatibilities
- Acids (violent neutralization), aluminium, zinc, tin (generates hydrogen gas), halogens, organic nitro compounds.Class-level guidance — not product-specific; the SDS controls.
- Shelf Life
- 36 monthsmedia.vwr.comSource states a 3 year shelf-life for a 50% (w/w) sodium hydroxide solution (BDH reagent grade catalog listing); no storage conditions are stated and the source does not name membrane grade.
For full hazard, PPE, and emergency response guidance, refer to the Safety Data Sheet (SDS) for this product. The SDS controls in all cases where guidance differs.
Packaging & Logistics
Shipping Description (US DOT)
UN1824, Sodium hydroxide solution, 8, PG II
Sourced from 49 CFR 172.101. Confirm against shipping documents and carrier requirements before tender.
Revision History
Last reviewed 2026-07-06 by Andre Taki, DOT Hazmat Specialist.
| Version | Date | Change | Trigger |
|---|---|---|---|
| 1.2 | 2026-07-22 | Canonical data updated: 2 fields changed via the provenance/adjudication pipeline.
| canonical_change |
| 1.1 | 2026-07-06 | Canonical data re-verified: 4 fields updated against independent vendor SDSs, CLP Annex VI, 49 CFR, and OSHA HazCom 2024 (GHS classification, hazard/precautionary codes, signal word, physical properties as applicable).
| canonical_change |
| 1.0 | 2026-05-20 | Initial URL-first TDS published from canonical chemistry registry. | initial |
This Technical Data Sheet is provided for technical reference. The Safety Data Sheet (SDS) controls in all cases where guidance differs. Values reflect Alliance Chemical canonical data at time of generation; subsequent revisions are recorded in the Revision History above.